Lock - in Amplifier and Applications

Save this PDF as:
 WORD  PNG  TXT  JPG

Size: px
Start display at page:

Download "Lock - in Amplifier and Applications"

Transcription

1 Lock - in Amplifier and Applications What is a Lock in Amplifier? In a nut shell, what a lock-in amplifier does is measure the amplitude V o of a sinusoidal voltage, V in (t) = V o cos(ω o t) where ω o = 2πf o and f o are the angular- and natural frequencies of the signal respectively. You supply this voltage to the signal input of the lock-in, and its meter tells you the amplitude Vo, typically calibrated in V-rms. What makes a lock-in different from a simple AC voltmeter, which is what I just described, is that you must also supply the lock-in with a reference input, that is, a decent size, say 1 volt p-p, sinusoidal voltage that is synchronized with the signal whose amplitude you are trying to measure. The lock-in uses this signal (like an external trigger for an oscilloscope) to "find" the signal to be measured, while ignoring anything that is not synchronized with the reference. In practice, the lock-in can measure voltage amplitudes as small as a few nano volts, while ignoring signals even thousands of times larger. In contrast, an AC voltmeter would measure the sum of all of the voltages at its input. Let's consider an example. Suppose the signal is a 10 nv sine wave at 10 khz. Clearly some amplification is required to bring the signal above the noise. A good low noise amplifier will have about 5 nv/ Hz of input noise. If the amplifier bandwidth is 100 khz and the gain is 1000, then we can expect our output to be 10μV of signal (10 nv x 1000) and 1.6 mv of broadband noise (5 nv/ Hz x 100 khz x 1000). We won't have much luck measuring the output signal unless we single out the frequency of interest. If we follow the amplifier with a bandpass filter with a Q=100 (a VERY good filter) entered at 10 khz, any signal in a 100 Hz bandwidth will be detected (10 khz/q). The noise in the filter pass band will be 50 μv (5 nv/ Hz x 100 Hz x 1000) and the signal will still be 10 μv. The output noise is much greater than the signal and an accurate measurement can not be made. Further gain will not help the signal to noise problem. Now try following the amplifier with a phase-sensitive detector (PSD). The PSD can detect the signal at 10 khz with a bandwidth as narrow as 0.01 Hz! In this case, the noise in the detection bandwidth will be only 0.5 μv (5 nv/ Hz x.01 Hz x 1000) while the signal is still 10 μv. The signal to noise ratio is now 20 and an accurate measurement of the signal is possible.

2 What is Phase Sensitive Detection? Lock-in measurements require a frequency reference. Typically an experiment is excited at a fixed frequency (from an oscillator or function generator) and the lock-in detects the response from the experiment at the reference frequency. In the diagram below, the reference signal is a square wave at frequency ω r. This might be the sync output from a function generator. If the sine output from the function generator is used to excite the experiment, the response might be the signal waveform shown below. The signal is V sig sin(ω r t + θ sig ) where Vsig is the signal amplitude, ω r is the signal frequency, and θ sig is the signal s phase. Lock-in amplifiers generate their own internal reference signal usually by a phase-locked-loop locked to the external reference. In the diagram below the external reference, the lock-in s reference and the signal are all shown. The internal reference is V L sin(ω o t + θ ref ). The lock in amplifies the signal and then multiplies it by the lock-in reference using a phase-sensitive detector or multiplier. The output of the PSD is simply the product of two sine waves. V psd = V sig V L sin(w r t + θ sig )sin(ω L t + θ ref ) = 1/2 V sig V L cos([ω r - ω L ]t + θ sig - θ ref ) - 1/2 V sig V L cos([ω r + ω L ]t + θ sig + θ ref ) The PSD output is two AC signals, one at the difference frequency (ω r - ω L ) and the other at the sum frequency (ω r + ω L ). If the PSD output is passed through a low pass filter, the AC signals are removed. What will be left? In the general case, nothing.

3 However, if ω r equals ω L, the difference frequency component will be a DC signal. In this case, the filtered PSD output will be V psd = 1/2 V sig V L cos(θ sig - θ ref ). This is a very nice signal it is a DC signal proportional to the signal amplitude. It s important to consider the physical nature of this multiplication and filtering process in different types of lock-ins. In traditional analog lock-ins the signal and reference are analog voltage signals. The signal and reference are multiplied in an analog multiplier, and the result is filtered with one or more stages of RC filters. In a digital lock-in such as the SR850, the signal and reference are represented by sequences of numbers. Multiplication and filtering are performed mathematically by a digital signal processing (DSP) chip. We ll discuss this in more detail later. Block Diagram While a lock-in amplifier is an extremely important and powerful measuring tool, it is also quite simple. The block diagram of a lock-in amplifier is shown in Figure 1. The lock-in consists of five stages: 1. AC amplifier, called the signal amplifier; 2. Voltage controlled oscillator (VCO); 3. Multiplier, called the phase sensitive detector (PSD); 4. Low-pass filter; and 5. DC amplifier. The signal to be measured is fed into the input of the AC Amplifier. The output of the DC amplifier is a DC voltage proportional to V 0. This voltage is displayed on the lock-in's own meter, and is also available at the output connector. I now elaborate on the functions of the five stages.

4 The AC amplifier is simply a voltage amplifier combined with variable filters. Some lock-in amplifiers let you change the filters as you wish, others do not. Some lock-in amplifiers have the output of the AC amplifier stage available at the signal monitor output. Many do not. The voltage controlled oscillator is just an oscillator, except that it can synchronize with an external reference signal (i.e., trigger) both in phase and frequency. Some lock-in amplifiers contain a complete oscillator and need no external reference. In this case they operate at the frequency and amplitude that you set, and you must use their oscillator output in your experiment to derive the signal that you ultimately wish to measure. Virtually all lock-in amplifiers are able to synchronize with an external reference signal. The VCO also contains a phase-shifting circuit that allows the user to shift its signal from degrees with respect to the reference. The phase sensitive detector is a circuit which takes in two voltages as inputs V1 and V2 and produces an output which is the product V 1 *V 2. That is, the PSD is just a multiplier circuit. The low pass filter is an RC filter whose time constant may be selected. In many cases you may choose to have one RC filter stage (single pole filter) or two RC filter stages in series (2-pole filter). In newer lock-in amplifiers, this might be a digital filter with the attenuation of a "many pole" filter. The DC amplifier is just a low-frequency amplifier similar to those frequently assembled with op-amps. It differs from the AC amplifier in that it works all the way down to zero frequency (DC) and is not intended to work well at very high frequencies, say above 10 KHz. Time Constant and DC Gain The output of the PSD contains many signals. Most of the output signals have frequencies which are either the sum or difference between an input signal frequency and the reference frequency. Only the component of the input signal whose frequency is exactly equal to the reference frequency will result in a DC output. The low pass filter at the PSD output removes all of the unwanted AC signals, both the 2F (sum of the signal and the reference) and the noise components. This filter is what makes the lock-in such a narrow band detector. Time Constants Lock-in amplifiers have traditionally set the low pass filter bandwidth by setting the time constant. The time constant is simply 1/2pf where f is the -3 db frequency of the filter. The low pass filters are simple 6 db/oct roll off, RC type filters. A 1 second time constant referred to a filter whose -3 db point occurred at 0.16 Hz and rolled off at 6 db/oct beyond 0.16 Hz. Typically, there are two successive filters so that the overall filter can roll off at either 6 db or 12 db per octave. The time constant referred to the -3

5 db point of each filter alone (not the combined filter). The notion of time constant arises from the fact that the actual output is supposed to be a DC signal. In fact, when there is noise at the input, there is noise on the output. By increasing the time constant, the output becomes more steady and easier to measure reliably. The trade off comes when real changes in the input signal take many time constants to be reflected at the output. This is because a single RC filter requires about 5 time constants to settle to its final value. The time constant reflects how slowly the output responds, and thus the degree of output smoothing. The time constant also determines the equivalent noise bandwidth (ENBW) for noise measurements. The ENBW is NOT the filter -3 db pole, it is the effective bandwidth for Gaussian noise. DC Output Gain How big is the DC output from the PSD? It depends on the dynamic reserve. With 60 db of dynamic reserve, a noise signal can be 1000 times (60 db) greater than a full scale signal. At the PSD, the noise can not exceed the PSD's input range. In an analog lock-in, the PSD input range might be 5V. With 60 db of dynamic reserve, the signal will be only 5 mv at the PSD input. The PSD typically has no gain so the DC output from the PSD will only be a few mill volts! Even if the PSD had no DC output errors, amplifying this mill volt signal up to 10 V is error prone. The DC output gain needs to be about the same as the dynamic reserve (1000 in this case) to provide a 10 V output for a full scale input signal. An offset as small as 1 mv will appear as 1 V at the output! In fact, the PSD output offset plus the input offset of the DC amplifier needs to be on the order of 10 μv in order to not affect the measurement. If the dynamic reserve is increased to 80dB, then this offset needs to be 10 times smaller still. This is one of the reasons why analog lockins do not perform well at very high dynamic reserve. The digital lock-in does not have an analog DC amplifier. The output gain is yet another function handled by the digital signal processor. We already know that the digital PSD has no DC output offset. Likewise, the digital DC amplifier has no input offset. Amplification is simply taking input numbers and multiplying by the gain. This allows the SR830 to operate with 100 db of dynamic reserve without any output offset or zero drift.

6

7

8

OPERATIONAL AMPLIFIERS. o/p

OPERATIONAL AMPLIFIERS. o/p OPERATIONAL AMPLIFIERS 1. If the input to the circuit of figure is a sine wave the output will be i/p o/p a. A half wave rectified sine wave b. A fullwave rectified sine wave c. A triangular wave d. A

More information

An introduction to synchronous detection. A.Platil

An introduction to synchronous detection. A.Platil An introduction to synchronous detection A.Platil Overview: Properties of SD Fourier transform and spectra General synchronous detector (AKA lock-in amplifier, syn. demodulator, Phase Sensitive Detector)

More information

Lab 9: Op Amps Lab Assignment

Lab 9: Op Amps Lab Assignment 3 class days 1. Differential Amplifier Source: Hands-On chapter 8 (~HH 6.1) Lab 9: Op Amps Lab Assignment Difference amplifier. The parts of the pot on either side of the slider serve as R3 and R4. The

More information

ANALYZER BASICS WHAT IS AN FFT SPECTRUM ANALYZER? 2-1

ANALYZER BASICS WHAT IS AN FFT SPECTRUM ANALYZER? 2-1 WHAT IS AN FFT SPECTRUM ANALYZER? ANALYZER BASICS The SR760 FFT Spectrum Analyzer takes a time varying input signal, like you would see on an oscilloscope trace, and computes its frequency spectrum. Fourier's

More information

Lab 4 Op Amp Filters

Lab 4 Op Amp Filters Lab 4 Op Amp Filters Figure 4.0. Frequency Characteristics of a BandPass Filter Adding a few capacitors and resistors to the basic operational amplifier (op amp) circuit can yield many interesting analog

More information

Filters and Waveform Shaping

Filters and Waveform Shaping Physics 333 Experiment #3 Fall 211 Filters and Waveform Shaping Purpose The aim of this experiment is to study the frequency filtering properties of passive (R, C, and L) circuits for sine waves, and the

More information

PH 210 Electronics Laboratory I Instruction Manual

PH 210 Electronics Laboratory I Instruction Manual PH 210 Electronics Laboratory I Instruction Manual Index Page No General Instructions 2 Experiment 1 Common Emitter (CE) Amplifier 4 Experiment 2 Multistage amplifier: Cascade of two CE stages 7 Experiment

More information

Frequency Response of Filters

Frequency Response of Filters School of Engineering Department of Electrical and Computer Engineering 332:224 Principles of Electrical Engineering II Laboratory Experiment 2 Frequency Response of Filters 1 Introduction Objectives To

More information

Op-Amp Simulation EE/CS 5720/6720. Read Chapter 5 in Johns & Martin before you begin this assignment.

Op-Amp Simulation EE/CS 5720/6720. Read Chapter 5 in Johns & Martin before you begin this assignment. Op-Amp Simulation EE/CS 5720/6720 Read Chapter 5 in Johns & Martin before you begin this assignment. This assignment will take you through the simulation and basic characterization of a simple operational

More information

RightMark Audio Analyzer

RightMark Audio Analyzer RightMark Audio Analyzer Version 2.5 2001 http://audio.rightmark.org Tests description 1 Contents FREQUENCY RESPONSE TEST... 2 NOISE LEVEL TEST... 3 DYNAMIC RANGE TEST... 5 TOTAL HARMONIC DISTORTION TEST...

More information

Class A Amplifier Design

Class A Amplifier Design Module 2 Amplifiers Introduction to Amplifier Design What you ll learn in Module 2. Basic design process. Section 2.0 Introduction to Amplifier Design. Section 2.1 DC Conditions. Design a BJT class A common

More information

Vi, fi input. Vphi output VCO. Vosc, fosc. voltage-controlled oscillator

Vi, fi input. Vphi output VCO. Vosc, fosc. voltage-controlled oscillator Experiment #4 CMOS 446 Phase-Locked Loop c 1997 Dragan Maksimovic Department of Electrical and Computer Engineering University of Colorado, Boulder The purpose of this lab assignment is to introduce operating

More information

Chapter 12: The Operational Amplifier

Chapter 12: The Operational Amplifier Chapter 12: The Operational Amplifier 12.1: Introduction to Operational Amplifier (Op-Amp) Operational amplifiers (op-amps) are very high gain dc coupled amplifiers with differential inputs; they are used

More information

The unique waveform control section starts with simple familiar waves and curves them into waves you haven't heard before.

The unique waveform control section starts with simple familiar waves and curves them into waves you haven't heard before. The Q167 LFO++ is a Low Frequency Oscillator and universal modulator with a wide range of interesting features. This functionally-dense module creates complex modulation with a variety of common and unusual

More information

The Electronic Scale

The Electronic Scale The Electronic Scale Learning Objectives By the end of this laboratory experiment, the experimenter should be able to: Explain what an operational amplifier is and how it can be used in amplifying signal

More information

Reading: HH Sections 4.11 4.13, 4.19 4.20 (pgs. 189-212, 222 224)

Reading: HH Sections 4.11 4.13, 4.19 4.20 (pgs. 189-212, 222 224) 6 OP AMPS II 6 Op Amps II In the previous lab, you explored several applications of op amps. In this exercise, you will look at some of their limitations. You will also examine the op amp integrator and

More information

EXPERIMENT NUMBER 5 BASIC OSCILLOSCOPE OPERATIONS

EXPERIMENT NUMBER 5 BASIC OSCILLOSCOPE OPERATIONS 1 EXPERIMENT NUMBER 5 BASIC OSCILLOSCOPE OPERATIONS The oscilloscope is the most versatile and most important tool in this lab and is probably the best tool an electrical engineer uses. This outline guides

More information

The front end of the receiver performs the frequency translation, channel selection and amplification of the signal.

The front end of the receiver performs the frequency translation, channel selection and amplification of the signal. Many receivers must be capable of handling a very wide range of signal powers at the input while still producing the correct output. This must be done in the presence of noise and interference which occasionally

More information

Lab 1: The Digital Oscilloscope

Lab 1: The Digital Oscilloscope PHYSICS 220 Physical Electronics Lab 1: The Digital Oscilloscope Object: To become familiar with the oscilloscope, a ubiquitous instrument for observing and measuring electronic signals. Apparatus: Tektronix

More information

Experiment # (4) AM Demodulator

Experiment # (4) AM Demodulator Islamic University of Gaza Faculty of Engineering Electrical Department Experiment # (4) AM Demodulator Communications Engineering I (Lab.) Prepared by: Eng. Omar A. Qarmout Eng. Mohammed K. Abu Foul Experiment

More information

AMETEK s Elgar SW and California Instruments CSW Form, Fit and Functions Comparison

AMETEK s Elgar SW and California Instruments CSW Form, Fit and Functions Comparison AMETEK s Elgar SW and California Instruments CSW Form, Fit and Functions Comparison Introduction The purpose of this technical note is to compare the differences between the discontinued Elgar SW Series

More information

ENGR 210 Lab 11 Frequency Response of Passive RC Filters

ENGR 210 Lab 11 Frequency Response of Passive RC Filters ENGR 210 Lab 11 Response of Passive RC Filters The objective of this lab is to introduce you to the frequency-dependent nature of the impedance of a capacitor and the impact of that frequency dependence

More information

Electrical Resonance

Electrical Resonance Electrical Resonance (R-L-C series circuit) APPARATUS 1. R-L-C Circuit board 2. Signal generator 3. Oscilloscope Tektronix TDS1002 with two sets of leads (see Introduction to the Oscilloscope ) INTRODUCTION

More information

Lab 3. Transistor and Logic Gates

Lab 3. Transistor and Logic Gates Lab 3. Transistor and Logic Gates Laboratory Instruction Today you will learn how to use a transistor to amplify a small AC signal as well as using it as a switch to construct digital logic circuits. Introduction

More information

Meters, Power Supplies and Generators

Meters, Power Supplies and Generators 1. Meters Meters, Power Supplies and Generators Generally analog meters respond to the average of the signal being measured. This is due to the mechanical mass of the pointer and the RC response time of

More information

CIRCUITS LABORATORY EXPERIMENT 3. AC Circuit Analysis

CIRCUITS LABORATORY EXPERIMENT 3. AC Circuit Analysis CIRCUITS LABORATORY EXPERIMENT 3 AC Circuit Analysis 3.1 Introduction The steady-state behavior of circuits energized by sinusoidal sources is an important area of study for several reasons. First, the

More information

Introduction to Receivers

Introduction to Receivers Introduction to Receivers Purpose: translate RF signals to baseband Shift frequency Amplify Filter Demodulate Why is this a challenge? Interference (selectivity, images and distortion) Large dynamic range

More information

EXPERIMENT 1.2 CHARACTERIZATION OF OP-AMP

EXPERIMENT 1.2 CHARACTERIZATION OF OP-AMP 1.17 EXPERIMENT 1.2 CHARACTERIZATION OF OPAMP 1.2.1 OBJECTIVE 1. To sketch and briefly explain an operational amplifier circuit symbol and identify all terminals 2. To list the amplifier stages in a typical

More information

Lock-in amplifiers. A short tutorial by R. Scholten

Lock-in amplifiers. A short tutorial by R. Scholten Lock-in amplifiers A short tutorial by R. cholten Measuring something Common task: measure light intensity, e.g. absorption spectrum Need very low intensity to reduce broadening Noise becomes a problem

More information

The OP AMP -, Figure 1

The OP AMP -, Figure 1 The OP AMP Amplifiers, in general, taking as input, one or more electrical signals, and produce as output, one or more variations of these signals. The most common use of an amplifier is to accept a small

More information

PHYS 331: Junior Physics Laboratory I Notes on Noise Reduction

PHYS 331: Junior Physics Laboratory I Notes on Noise Reduction PHYS 331: Junior Physics Laboratory I Notes on Noise Reduction When setting out to make a measurement one often finds that the signal, the quantity we want to see, is masked by noise, which is anything

More information

Pulse Width Modulation

Pulse Width Modulation Pulse Width Modulation Pulse width modulation (PWM) is a technique in which a series of digital pulses is used to control an analog circuit. The length and frequency of these pulses determines the total

More information

The Calculation of G rms

The Calculation of G rms The Calculation of G rms QualMark Corp. Neill Doertenbach The metric of G rms is typically used to specify and compare the energy in repetitive shock vibration systems. However, the method of arriving

More information

EDEXCEL NATIONAL CERTIFICATE/DIPLOMA UNIT 5 - ELECTRICAL AND ELECTRONIC PRINCIPLES NQF LEVEL 3 OUTCOME 4 - ALTERNATING CURRENT

EDEXCEL NATIONAL CERTIFICATE/DIPLOMA UNIT 5 - ELECTRICAL AND ELECTRONIC PRINCIPLES NQF LEVEL 3 OUTCOME 4 - ALTERNATING CURRENT EDEXCEL NATIONAL CERTIFICATE/DIPLOMA UNIT 5 - ELECTRICAL AND ELECTRONIC PRINCIPLES NQF LEVEL 3 OUTCOME 4 - ALTERNATING CURRENT 4 Understand single-phase alternating current (ac) theory Single phase AC

More information

Using an Oscilloscope

Using an Oscilloscope Using an Oscilloscope The oscilloscope is used to measure a voltage that changes in time. It has two probes, like a voltmeter. You put these probes on either side of the thing that you want to measure

More information

Experiment # (7) FSK Modulator

Experiment # (7) FSK Modulator Islamic University of Gaza Faculty of Engineering Electrical Department Experiment # (7) FSK Modulator Digital Communications Lab. Prepared by: Eng. Mohammed K. Abu Foul Experiment Objectives: 1. To understand

More information

Loop Bandwidth and Clock Data Recovery (CDR) in Oscilloscope Measurements. Application Note 1304-6

Loop Bandwidth and Clock Data Recovery (CDR) in Oscilloscope Measurements. Application Note 1304-6 Loop Bandwidth and Clock Data Recovery (CDR) in Oscilloscope Measurements Application Note 1304-6 Abstract Time domain measurements are only as accurate as the trigger signal used to acquire them. Often

More information

Clock Recovery in Serial-Data Systems Ransom Stephens, Ph.D.

Clock Recovery in Serial-Data Systems Ransom Stephens, Ph.D. Clock Recovery in Serial-Data Systems Ransom Stephens, Ph.D. Abstract: The definition of a bit period, or unit interval, is much more complicated than it looks. If it were just the reciprocal of the data

More information

Bipolar Transistor Amplifiers

Bipolar Transistor Amplifiers Physics 3330 Experiment #7 Fall 2005 Bipolar Transistor Amplifiers Purpose The aim of this experiment is to construct a bipolar transistor amplifier with a voltage gain of minus 25. The amplifier must

More information

SUMMARY. Additional Digital/Software filters are included in Chart and filter the data after it has been sampled and recorded by the PowerLab.

SUMMARY. Additional Digital/Software filters are included in Chart and filter the data after it has been sampled and recorded by the PowerLab. This technique note was compiled by ADInstruments Pty Ltd. It includes figures and tables from S.S. Young (2001): Computerized data acquisition and analysis for the life sciences. For further information

More information

The Oscilloscope, the Signal Generator and Your Filter s Test Setup SGM 5/29/2013

The Oscilloscope, the Signal Generator and Your Filter s Test Setup SGM 5/29/2013 The Oscilloscope, the Signal Generator and Your Filter s Test Setup SGM 5/29/2013 1. Oscilloscope A multimeter is an appropriate device to measure DC voltages, however, when a signal alternates at relatively

More information

Filters & Wave Shaping

Filters & Wave Shaping Module 8 AC Theory Filters & Wave Shaping Passive Filters & Wave Shaping What you'll learn in Module 8. Module 8 Introduction Recognise passive filters with reference to their response curves. High pass,

More information

In modern electronics, it is important to be able to separate a signal into different

In modern electronics, it is important to be able to separate a signal into different Introduction In modern electronics, it is important to be able to separate a signal into different frequency regions. In analog electronics, four classes of filters exist to process an input signal: low-pass,

More information

Typical Doppler Signal Amplifier Application Note AN-04

Typical Doppler Signal Amplifier Application Note AN-04 Typical Doppler Signal Amplifier Application Note AN-04 RFbeam Microwave GmbH www.rfbeam.ch April 16, 2012 1/5 About This Document This application note describes a simple IF signal amplifier for Radar

More information

CONVERTERS. Filters Introduction to Digitization Digital-to-Analog Converters Analog-to-Digital Converters

CONVERTERS. Filters Introduction to Digitization Digital-to-Analog Converters Analog-to-Digital Converters CONVERTERS Filters Introduction to Digitization Digital-to-Analog Converters Analog-to-Digital Converters Filters Filters are used to remove unwanted bandwidths from a signal Filter classification according

More information

Experiment V: The AC Circuit, Impedance, and Applications to High and Low Pass Filters

Experiment V: The AC Circuit, Impedance, and Applications to High and Low Pass Filters Experiment : The AC Circuit, Impedance, and Applications to High and Low Pass Filters I. eferences Halliday, esnick and Krane, Physics, ol. 2, 4th Ed., Chapters 33 Purcell, Electricity and Magnetism, Chapter

More information

Precision Diode Rectifiers

Precision Diode Rectifiers by Kenneth A. Kuhn March 21, 2013 Precision half-wave rectifiers An operational amplifier can be used to linearize a non-linear function such as the transfer function of a semiconductor diode. The classic

More information

Laboratory 4: Feedback and Compensation

Laboratory 4: Feedback and Compensation Laboratory 4: Feedback and Compensation To be performed during Week 9 (Oct. 20-24) and Week 10 (Oct. 27-31) Due Week 11 (Nov. 3-7) 1 Pre-Lab This Pre-Lab should be completed before attending your regular

More information

Transistor Amplifiers

Transistor Amplifiers Physics 3330 Experiment #7 Fall 1999 Transistor Amplifiers Purpose The aim of this experiment is to develop a bipolar transistor amplifier with a voltage gain of minus 25. The amplifier must accept input

More information

Figure 1. Front Panel of Function Generator

Figure 1. Front Panel of Function Generator Equipment Introduction: Part I - Introduction to the Function Generator Overview: The function generator is used to generate a wide range of alternating-current (AC) signals. A diagram of the Leader LFG-1300S

More information

The Oscilloscope and the Function Generator:

The Oscilloscope and the Function Generator: The Oscilloscope and the Function Generator: Some introductory exercises for students in the advanced labs Introduction So many of the experiments in the advanced labs make use of oscilloscopes and function

More information

Positive Feedback and Oscillators

Positive Feedback and Oscillators Physics 3330 Experiment #6 Fall 1999 Positive Feedback and Oscillators Purpose In this experiment we will study how spontaneous oscillations may be caused by positive feedback. You will construct an active

More information

TESTS OF 1 MHZ SIGNAL SOURCE FOR SPECTRUM ANALYZER CALIBRATION 7/8/08 Sam Wetterlin

TESTS OF 1 MHZ SIGNAL SOURCE FOR SPECTRUM ANALYZER CALIBRATION 7/8/08 Sam Wetterlin TESTS OF 1 MHZ SIGNAL SOURCE FOR SPECTRUM ANALYZER CALIBRATION 7/8/08 Sam Wetterlin (Updated 7/19/08 to delete sine wave output) I constructed the 1 MHz square wave generator shown in the Appendix. This

More information

Introduction 1 Block diagram 1

Introduction 1 Block diagram 1 Electric Druid VCLFO Introduction 1 Block diagram 1 Features 2 Fastest LFO frequency of around 12.8Hz 2 Slowest LFO frequency of around 0.05Hz 2 10-bit LFO output resolution 2 19.5KHz sample output rate

More information

Making Accurate Voltage Noise and Current Noise Measurements on Operational Amplifiers Down to 0.1Hz

Making Accurate Voltage Noise and Current Noise Measurements on Operational Amplifiers Down to 0.1Hz Author: Don LaFontaine Making Accurate Voltage Noise and Current Noise Measurements on Operational Amplifiers Down to 0.1Hz Abstract Making accurate voltage and current noise measurements on op amps in

More information

UNIVERSITY OF NORTH CAROLINA AT CHARLOTTE. Department of Electrical and Computer Engineering

UNIVERSITY OF NORTH CAROLINA AT CHARLOTTE. Department of Electrical and Computer Engineering UNIVERSITY OF NORTH CAROLINA AT CHARLOTTE Department of Electrical and Computer Engineering Experiment No. 5 - Gain-Bandwidth Product and Slew Rate Overview: In this laboratory the student will explore

More information

FREQUENCY RESPONSE OF AN AUDIO AMPLIFIER

FREQUENCY RESPONSE OF AN AUDIO AMPLIFIER 2014 Amplifier - 1 FREQUENCY RESPONSE OF AN AUDIO AMPLIFIER The objectives of this experiment are: To understand the concept of HI-FI audio equipment To generate a frequency response curve for an audio

More information

CRP718 RF and Microwave Measurements Laboratory

CRP718 RF and Microwave Measurements Laboratory CRP718 RF and Microwave Measurements Laboratory Experiment- MW2 Handout. Updated Jan 13, 2011 SPECTRUM ANALYZER BASED MEASUREMENTS (groups of 2 may omit part 2.1, but are advised to study the procedures

More information

Infrared PWM Receiver

Infrared PWM Receiver ECE 2C Laboratory Manual 5 Infrared PWM Receiver Overview In this lab you will construct the receiver circuit to complement the PWM transmitter board you assembled last week. This receiver detects, amplifies,

More information

Voltage. Oscillator. Voltage. Oscillator

Voltage. Oscillator. Voltage. Oscillator fpa 147 Week 6 Synthesis Basics In the early 1960s, inventors & entrepreneurs (Robert Moog, Don Buchla, Harold Bode, etc.) began assembling various modules into a single chassis, coupled with a user interface

More information

R f. V i. ET 438a Automatic Control Systems Technology Laboratory 4 Practical Differentiator Response

R f. V i. ET 438a Automatic Control Systems Technology Laboratory 4 Practical Differentiator Response ET 438a Automatic Control Systems Technology Laboratory 4 Practical Differentiator Response Objective: Design a practical differentiator circuit using common OP AMP circuits. Test the frequency response

More information

Part 2: Receiver and Demodulator

Part 2: Receiver and Demodulator University of Pennsylvania Department of Electrical and Systems Engineering ESE06: Electrical Circuits and Systems II Lab Amplitude Modulated Radio Frequency Transmission System Mini-Project Part : Receiver

More information

Basic Op Amp Circuits

Basic Op Amp Circuits Basic Op Amp ircuits Manuel Toledo INEL 5205 Instrumentation August 3, 2008 Introduction The operational amplifier (op amp or OA for short) is perhaps the most important building block for the design of

More information

LABORATORY 1 WRITEUP - PHYSICS 517/617. Prof. L. S. Durkin July 5, 1992

LABORATORY 1 WRITEUP - PHYSICS 517/617. Prof. L. S. Durkin July 5, 1992 LABORATORY 1 WRITEUP - PHYSICS 517/617 Prof. L. S. Durkin July 5, 1992 DISCLAIMER: There are many ways to write up a lab report, none of them superior to any other. Below is an example of an acceptable

More information

Name Date Day/Time of Lab Partner(s) Lab TA

Name Date Day/Time of Lab Partner(s) Lab TA Name Date Day/Time of Lab Partner(s) Lab TA Objectives LAB 7: AC CIRCUITS To understand the behavior of resistors, capacitors, and inductors in AC Circuits To understand the physical basis of frequency-dependent

More information

Wiard GR-341 Classic VCO Rev:

Wiard GR-341 Classic VCO Rev: Wiard GR-341 Classic VCO Rev: 031001 Classic VCO Audio Control Voltage Generator 5 waveforms at audio rate In low range acts as LFO, AR envelope One circuit - VCO1 Processor VCA does amplitude control,

More information

Agilent AN 1316 Optimizing Spectrum Analyzer Amplitude Accuracy

Agilent AN 1316 Optimizing Spectrum Analyzer Amplitude Accuracy Agilent AN 1316 Optimizing Spectrum Analyzer Amplitude Accuracy Application Note RF & Microwave Spectrum Analyzers Table of Contents 3 3 4 4 5 7 8 8 13 13 14 16 16 Introduction Absolute versus relative

More information

EXERCISES in ELECTRONICS and SEMICONDUCTOR ENGINEERING

EXERCISES in ELECTRONICS and SEMICONDUCTOR ENGINEERING Department of Electrical Drives and Power Electronics EXERCISES in ELECTRONICS and SEMICONDUCTOR ENGINEERING Valery Vodovozov and Zoja Raud http://learnelectronics.narod.ru Tallinn 2012 2 Contents Introduction...

More information

Step 1: Create the voltage source.

Step 1: Create the voltage source. Glucose meter In this lab we will build a blood glucose meter, similar to the commercial devices that are used to monitor glucose levels in patients with diabetes. Diabetes is a serious disease which affects

More information

CMOY Headphone Project Electronic Lab Phys 318

CMOY Headphone Project Electronic Lab Phys 318 Project Overview There are two kinds of circuits that need to be built for the headphone amplifier project. ) A power circuit 2) Two amplifier circuits You will build one of each of these circuits on a

More information

APPLICATION NOTE 29 Testing Capacitors with High DC Bias

APPLICATION NOTE 29 Testing Capacitors with High DC Bias APPLICATION NOTE 29 Testing Capacitors with High DC Bias This application note will describe the process of analysing the impedance of a capacitor when subjected to high DC bias voltages. This particular

More information

LABORATORY EXPERIMENT. Infrared Transmitter/Receiver

LABORATORY EXPERIMENT. Infrared Transmitter/Receiver LABORATORY EXPERIMENT Infrared Transmitter/Receiver (Note to Teaching Assistant: The week before this experiment is performed, place students into groups of two and assign each group a specific frequency

More information

Johnson Noise Dec. 23, 1998

Johnson Noise Dec. 23, 1998 Physics 623 Johnson Noise Dec. 23, 1998 Answer the questions 1 through 15 in this writeup before coming to the lab. They will be collected at the beginning of the lab. Read the sections of the text referenced

More information

BASIC ELECTRONICS PROF. T.S. NATARAJAN DEPT OF PHYSICS IIT MADRAS

BASIC ELECTRONICS PROF. T.S. NATARAJAN DEPT OF PHYSICS IIT MADRAS BASIC ELECTRONICS PROF. T.S. NATARAJAN DEPT OF PHYSICS IIT MADRAS LECTURE-12 TRANSISTOR BIASING Emitter Current Bias Thermal Stability (RC Coupled Amplifier) Hello everybody! In our series of lectures

More information

Bharathwaj Muthuswamy EE100 Active Filters

Bharathwaj Muthuswamy EE100 Active Filters Bharathwaj Muthuswamy EE100 mbharat@cory.eecs.berkeley.edu 1. Introduction Active Filters In this chapter, we will deal with active filter circuits. Why even bother with active filters? Answer: Audio.

More information

AC Measurements Using the Oscilloscope and Multimeter by Mr. David Fritz

AC Measurements Using the Oscilloscope and Multimeter by Mr. David Fritz AC Measurements Using the Oscilloscope and Multimeter by Mr. David Fritz 1 Sine wave with a DC offset f = frequency in Hz A = DC offset voltage (average voltage) B = Sine amplitude Vpp = 2B Vmax = A +

More information

Soundcard Based Noise Figure Alignment Aid

Soundcard Based Noise Figure Alignment Aid Soundcard Based Noise Figure Alignment Aid G4JNT & G3PLX November 2011 Back in 1974, John Compton, G4COM, published an Automatic Noise Figure Alignment aid that automatically controlled a noise source

More information

APPLICATION NOTE AP050830

APPLICATION NOTE AP050830 APPLICATION NOTE AP050830 Selection and use of Ultrasonic Ceramic Transducers Pro-Wave Electronics Corp. E-mail: sales@pro-wave.com.tw URL: http://www.prowave.com.tw The purpose of this application note

More information

Programmable-Gain Transimpedance Amplifiers Maximize Dynamic Range in Spectroscopy Systems

Programmable-Gain Transimpedance Amplifiers Maximize Dynamic Range in Spectroscopy Systems Programmable-Gain Transimpedance Amplifiers Maximize Dynamic Range in Spectroscopy Systems PHOTODIODE VOLTAGE SHORT-CIRCUIT PHOTODIODE SHORT- CIRCUIT VOLTAGE 0mV DARK ark By Luis Orozco Introduction Precision

More information

PCM Encoding and Decoding:

PCM Encoding and Decoding: PCM Encoding and Decoding: Aim: Introduction to PCM encoding and decoding. Introduction: PCM Encoding: The input to the PCM ENCODER module is an analog message. This must be constrained to a defined bandwidth

More information

MATRIX TECHNICAL NOTES

MATRIX TECHNICAL NOTES 200 WOOD AVENUE, MIDDLESEX, NJ 08846 PHONE (732) 469-9510 FAX (732) 469-0418 MATRIX TECHNICAL NOTES MTN-107 TEST SETUP FOR THE MEASUREMENT OF X-MOD, CTB, AND CSO USING A MEAN SQUARE CIRCUIT AS A DETECTOR

More information

Constructing a precision SWR meter and antenna analyzer. Mike Brink HNF, Design Technologist.

Constructing a precision SWR meter and antenna analyzer. Mike Brink HNF, Design Technologist. Constructing a precision SWR meter and antenna analyzer. Mike Brink HNF, Design Technologist. Abstract. I have been asked to put together a detailed article on a SWR meter. In this article I will deal

More information

SIGNAL GENERATORS and OSCILLOSCOPE CALIBRATION

SIGNAL GENERATORS and OSCILLOSCOPE CALIBRATION 1 SIGNAL GENERATORS and OSCILLOSCOPE CALIBRATION By Lannes S. Purnell FLUKE CORPORATION 2 This paper shows how standard signal generators can be used as leveled sine wave sources for calibrating oscilloscopes.

More information

H BRIDGE INVERTER. Vdc. Corresponding values of Va and Vb A+ closed, Va = Vdc A closed, Va = 0 B+ closed, Vb = Vdc B closed, Vb = 0 A+ B+ A B

H BRIDGE INVERTER. Vdc. Corresponding values of Va and Vb A+ closed, Va = Vdc A closed, Va = 0 B+ closed, Vb = Vdc B closed, Vb = 0 A+ B+ A B 1. Introduction How do we make AC from DC? Answer the H-Bridge Inverter. H BRIDGE INVERTER Vdc A+ B+ Switching rules Either A+ or A is always closed, but never at the same time * Either B+ or B is always

More information

Chapter 5. Basic Filters

Chapter 5. Basic Filters Chapter 5 Basic Filters 39 CHAPTER 5. BASIC FILTERS 5.1 Pre-Lab The answers to the following questions are due at the beginning of the lab. If they are not done at the beginning of the lab, no points will

More information

Lab #9: AC Steady State Analysis

Lab #9: AC Steady State Analysis Theory & Introduction Lab #9: AC Steady State Analysis Goals for Lab #9 The main goal for lab 9 is to make the students familar with AC steady state analysis, db scale and the NI ELVIS frequency analyzer.

More information

Sophomore Physics Laboratory (PH005/105)

Sophomore Physics Laboratory (PH005/105) CALIFORNIA INSTITUTE OF TECHNOLOGY PHYSICS MATHEMATICS AND ASTRONOMY DIVISION Sophomore Physics Laboratory (PH5/15) Analog Electronics Active Filters Copyright c Virgínio de Oliveira Sannibale, 23 (Revision

More information

Chapter 6 PLL and Clock Generator

Chapter 6 PLL and Clock Generator Chapter 6 PLL and Clock Generator The DSP56300 core features a Phase Locked Loop (PLL) clock generator in its central processing module. The PLL allows the processor to operate at a high internal clock

More information

Project: Pulse meter Idea: Use noninvasive infrared light to probe blood pressure and pulse rate in a finger tip. Uses: A variant of this device is

Project: Pulse meter Idea: Use noninvasive infrared light to probe blood pressure and pulse rate in a finger tip. Uses: A variant of this device is Project: Pulse meter Idea: Use noninvasive infrared light to probe blood pressure and pulse rate in a finger tip. Uses: A variant of this device is used routinely in hospitals and is called a pulse-oximeter.

More information

Abstract. Cycle Domain Simulator for Phase-Locked Loops

Abstract. Cycle Domain Simulator for Phase-Locked Loops Abstract Cycle Domain Simulator for Phase-Locked Loops Norman James December 1999 As computers become faster and more complex, clock synthesis becomes critical. Due to the relatively slower bus clocks

More information

Title : Analog Circuit for Sound Localization Applications

Title : Analog Circuit for Sound Localization Applications Title : Analog Circuit for Sound Localization Applications Author s Name : Saurabh Kumar Tiwary Brett Diamond Andrea Okerholm Contact Author : Saurabh Kumar Tiwary A-51 Amberson Plaza 5030 Center Avenue

More information

THE R551N RECEIVER FAQ FAULT FINDING THE REDIFON COMMUNICATIONS RECEIVER R551N. Date: October 10th 1995 by: Jan Verduyn G5BBL

THE R551N RECEIVER FAQ FAULT FINDING THE REDIFON COMMUNICATIONS RECEIVER R551N. Date: October 10th 1995 by: Jan Verduyn G5BBL THE R551N RECEIVER FAQ FAULT FINDING THE REDIFON COMMUNICATIONS RECEIVER R551N Introduction: Date: October 10th 1995 by: Jan Verduyn G5BBL Recently a number of Redifon R551N receivers have appeared on

More information

Lab 4 Band Pass and Band Reject Filters

Lab 4 Band Pass and Band Reject Filters Lab 4 Band Pass and Band Reject Filters Introduction During this lab you will design and build three filters. First you will build a broad-band band-pass filter by cascading the high-pass and low-pass

More information

CHAPTER 16 OSCILLATORS

CHAPTER 16 OSCILLATORS CHAPTER 16 OSCILLATORS 16-1 THE OSCILLATOR - are electronic circuits that generate an output signal without the necessity of an input signal. - It produces a periodic waveform on its output with only the

More information

Technology and Benefits of Programmable Linear Position Sensors (Based on Inductive Measurement)

Technology and Benefits of Programmable Linear Position Sensors (Based on Inductive Measurement) Technology and Benefits of Programmable Linear Position Sensors (Based on Inductive Measurement) This white paper describes new technology that enable engineers to easily program key functions into a linear

More information

INTERNATIONAL TELECOMMUNICATION UNION. SERIES O: SPECIFICATIONS FOR MEASURING EQUIPMENT Equipment for the measurement of analogue parameters

INTERNATIONAL TELECOMMUNICATION UNION. SERIES O: SPECIFICATIONS FOR MEASURING EQUIPMENT Equipment for the measurement of analogue parameters INTERNATIONAL TELECOMMUNICATION UNION CCITT O.41 THE INTERNATIONAL TELEGRAPH AND TELEPHONE CONSULTATIVE COMMITTEE (11/1988) SERIES O: SPECIFICATIONS FOR MEASURING EQUIPMENT Equipment for the measurement

More information

FILTER CIRCUITS. A filter is a circuit whose transfer function, that is the ratio of its output to its input, depends upon frequency.

FILTER CIRCUITS. A filter is a circuit whose transfer function, that is the ratio of its output to its input, depends upon frequency. FILTER CIRCUITS Introduction Circuits with a response that depends upon the frequency of the input voltage are known as filters. Filter circuits can be used to perform a number of important functions in

More information

Comparator and Schmitt Trigger

Comparator and Schmitt Trigger Comparator and Schmitt Trigger Comparator circuits find frequent application in measurement and instrumentation systems. Learning Objectives Understand the Op-Amp Comparator with and without an offset

More information

PHYS 2426 Engineering Physics II (Revised July 7, 2011) AC CIRCUITS: RLC SERIES CIRCUIT

PHYS 2426 Engineering Physics II (Revised July 7, 2011) AC CIRCUITS: RLC SERIES CIRCUIT PHYS 2426 Engineering Physics II (Revised July 7, 2011) AC CIRCUITS: RLC SERIES CIRCUIT INTRODUCTION The objective of this experiment is to study the behavior of an RLC series circuit subject to an AC

More information

INTERFERENCE OF SOUND WAVES

INTERFERENCE OF SOUND WAVES 1/2016 Sound 1/8 INTERFERENCE OF SOUND WAVES PURPOSE: To measure the wavelength, frequency, and propagation speed of ultrasonic sound waves and to observe interference phenomena with ultrasonic sound waves.

More information